docs: def activateAaPdpContextRequest(AccessPointName_presence=0,
                                  ProtocolConfigurationOptions_presence=0,
                                  GprsTimer_presence=0):
      """ACTIVATE AA PDP CONTEXT REQUEST Section 9.5.10"""
      a = TpPd(pd=0x8)
      b = MessageType(mesType=0x50)  # 01010000
      c = NetworkServiceAccessPointIdentifier()
      d = LlcServiceAccessPointIdentifier()
      e = QualityOfService()
      f = PacketDataProtocolAddress()
      packet = a / b / c / d / e / f
      if AccessPointName_presence is 1:
          g = AccessPointName(ieiAPN=0x28)
          packet = packet / g
      if ProtocolConfigurationOptions_presence is 1:
          h = ProtocolConfigurationOptions(ieiPCO=0x27)
          packet = packet / h
      if GprsTimer_presence is 1:
          i = GprsTimer(ieiGT=0x29)
          packet = packet / i
      return packet